Advanced Materials Research Vol. 413

Abstract: For buliding the mathmatical model of elastic deformation for rolls system with a composite back-up roll assemblled by the shrinkage fit, the roll sleeve and roll mandrel was studied individually, the bending force was acted on the working roll and the load acted on the contact zone was discreted segment by segment, then the deflection model of the working roll and the roll sleeve and roll mandrel was put forward based on the influence function method. According to the force equilibrim function and the deformation compatibility function between the roll sleeve, the roll mandrel and working roll, the solution matrix was listed and the solving programe was compiled to solve the deflection of working roll and composite back-up roll, the pressure between the working roll and the roll sleeve and the cross-section thickness of rolled strip. Therefore, it is an important theoretical foundation to improve the manufacturing technology and practical application of the composite back-up roll.

Abstract: Non-linear analysis of autoclaved aerated concrete (AAC) block masonry composite wall with column has been conducted using finite element software ABAQUS. First, the finite element results were verified with laboratory results of full-scale specimens. Effects of horizontal reinforcement ratio on seismic performance were investigated. The analysis indicates that shearing strength of the wall is affected by the openings greatly. Seismic performance is improved with the increase of horizontal reinforcement ratio. The effect of vertical stress on wall without openings is more than that on wall with openings. Bearing capacity of walls without openings has a linear relationship with the horizontal reinforcement ratio. And bearing capacity of walls with openings is related to the place where the reinforcements are installed as well as the horizontal reinforcement ratio.

Abstract: The effects of nanoSiO₂ content on the Engler viscosity and storage stability of asphalt emulsion as well as the performances of asphalt emulsion residue were investigated. The results indicate that the Engler viscosity increases and storage stability of the emulsion is improved as the nanoSiO₂ dosage increases from 0 wt % to 1.2 wt %. With the nanoSiO₂ content increasing, it represents a reduction in the ductility and penetration of the asphalt emulsions residue. However, compositions of saturate, aromatic, resin and asphaltene (SARA) of the asphalt emulsions residue change slightly. The viscosity of the asphalt emulsions residue increases as the nanoSiO₂ content increases from 0 wt % to 1.2 wt % at temperatures from 70 °C to 120 °C and changes slightly when the temperature is higher than 120 °C.

Abstract: By analyzing effort factors of epoxy coating adhesion such as water absorption, acid corrosion and cycles stress, the acid carrion behaviors of epoxy resins as coating under stress have be evaluated. The results showed that under solution swelling, mechanical load and aggressive media interaction, epoxy coating adhesion drop distinctly and completely lost the ability of corrosion protection.

Abstract: Carpenter Technology Corporation’s Custom 465® stainless steel is a state-of-the-art alloy which has seen its applications expanding at a rapid rate. This alloy is a premium double vacuum melted (VIM/VAR) martensitic precipitation hardening stainless steel that offers an excellent combination of strength, toughness, and corrosion resistance. With its exceptional properties, design engineers have specified the alloy for high-performance components in various industries, such as aerospace, industrial, energy, consumer and medical. The high strength, greater than 250 ksi (1722 MPa) typical, and toughness of the alloy have allowed Custom 465 stainless to be used as a high-strength upgrade to conventional PH stainless steels such as 13-8 and 17-4. The addition of corrosion resistance to the high strength and toughness properties has allowed the alloy to be used as a stainless alternative to non-stainless steels such as AISI 4340 and 300M. This paper will compare mechanical and corrosion resistance properties of Custom 465 stainless steel to those of other PH stainless steels such as 17-4, 15-5, and 13-8, as well as to those of other aerospace alloys such as 300M and AerMet® 100 alloy. In addition, examples of the varied uses of the alloy will be provided, these examples will highlight the benefits obtained by the use of Custom 465 stainless steel over the previous alloys of choice for the applications.

Abstract: The cutting temperature rules of cemented carbide tools YW2 during cutting austenitic manganese steel ZGMn13 were investigated by experiments through systematically changing cutting parameters (cutting speed, feed, cutting depth) under the condition of dry cutting. The experiential expressions for cutting temperature of tools were summarized while dominating factors for influencing cutting temperature were analyzed. The results show that accounting values by experiential formulae basically match actually measuring values by experiments which may play an important role in studying cutting law of austenitic manganese steel. Cutting speed plays a major role in determining the temperature of cutting tools, followed by feed rate and depth of cutting.

Abstract: Cold adhesion precoating and then induction fusing, as a new technique of preparing self-fused alloy coating, is presented. The workpiece was precoated with Ni60 powder by an adhesion agent. The precoating dried was heated by a high frequency induction with 100kw output power, 250kHz frequency. Its thermomagnetism, thermal resistivity and induction refusing mechanism were analysed to determine the technological parameters. Comparing the microstructures and the properties of the coatings by cold adhesion, thermal spraying and laser refusing, we may conclude that: (1) One side of the workpiece should be preheated to 200°C before induction, and the range of frequency induction should be selected as 200~250kHz. (2) The microstructure of the coating by cold adhesion is superior to that by thermal spraying, but the particle size range should be 0.047~0.044mm (200~320 meshes). (3) The corrosion resistance of Ni60 coating by cold adhesion is better than by thermal spraying, and the cold adhesion is the best way to prepare the wear resistant coating.

Abstract: The track-memory of omnidirectional fire robot is so useful in locating the robot in fire scene, ultrasonic location nor map-matching nor other methods in self-orientation are not suitable for fire robot because of the precision requirement and response speed, in this paper, a simplified method based on inertial measurement unit (IMU) is proposed, in this method the position of robot is calculated by the acceleration and angular velocity , and iterative equation is derived , as the omnidirectional fire robot is always used as a translational device, the rotations of the robot in triaxial-axis are zero, a more practical algorithm based on the triaxial accelerometer is established. A fire robot model has been set up, experiment both with smoothing curve path and un-smoothing curve path have been made, , the trajectorys are iteratived by the practical algorithm, the experimental results demonstrated the practicability and accuracy of the new simplified method.

Abstract: A method based on solution of the inverse heat conduction problem was presented for online stress monitoring and fatigue life analysis of boiler drums. The mathematical model of the drum temperature distribution is based on the assumptions that the difference of temperature along the longitudinal axis of the boiler drum is negligible with changes only in the radial direction and the circumferential direction, and that the outer surface of drum is thermally insulated. Combining this model with the control-volume method provides temperatures at different points on a cross-section of the drum. With the temperature data, the stresses of the boiler drum are derived according to the FEM and the life expectancy of it is calculated　based on the rain flow method. Applying this method to the cold start-up process of a 300 MW boiler demonstrated the absence of errors caused by the boundary condition assumptions on the inner surface of the drum and an applicable technique for the online stress monitoring and fatigue life analysis of boiler drums.

Abstract: Cement emulsified asphalt mixture is a kind of composite materials, which is comprised of organic and inorganic materials, such as emulsified asphalt and cement, and has both advantages of cement concrete and asphalt concrete. Aiming at the problems of cement emulsified asphalt mixture that adhesion decline and road performance down in the using of process, the Discrete Element Method (DEM) was used to simulate two different kinds of aggregate used in the mixture. Through comparing the splitting strength, stress-strain curve, fracture development situation, and so on, suitable aggregate type, limestone aggregate, was obtained, which had higher adhesion property with cement emulsified asphalt binders.